Hi Blanchy,
I agree with what Josh said...don't skimp on the oil but rather skim it off prior to serving (you can use this oil for your next curry for added flavour).
However, if you're insistent on reducing the oil, I'd suggest you're probably best off reducing it in your base rather than your main dish (as Jerry suggests).
In my opinion, if you skimp too much on the oil (particularly in the main dish...I personally wouldn't use less than about 75ml per serving), you run of the risk of making a poor tasting and poorly textured curry. The reason being that it is the oil that dissolves and distributes the volatile oils from your spices.
PS: thanks for trying the recipe and for posting your results and photos

.....why were you "really surprised"?